Durban - The Transnet warehouse in Rossburgh that was engulfed in flames on Friday contained large amounts of wax and plastic, the Ethekwini municipality said.
The smoke from the fire, which started in the morning, was moving over the city as a result of strong 40km/h - 50km/h south-westerly winds, the municipality said in a statement.
The smoke was, however, not coming down over the city, but being blown in a northerly direction.
Residents were advised to stay indoors and close all windows and doors, and switch off all air-conditioning systems.
A worker at the warehouse and a firefighter were injured in the blaze and rushed to hospital, Rescue Care spokesperson Garrith Jamieson said.
He said the wind was making firefighting efforts difficult.
Transnet spokesperson Molatwane Likhethe said they would investigate the cause of the blaze.